1. Field of the Invention
The invention relates to copper complexes of phosphorus compounds, to a process for their preparation and to their use in catalytic coupling reactions.
2. Brief Description of the Prior Art
Coupling reactions catalyzed by copper complexes of aryl halides or arylsulphonates with heteroatom functionalities, for example thiols, amines and amides, have been described in the literature.
Ligands thereof comprising oxygen or phosphorus compounds are frequently used. For example, Venkataraman et al. (Tetrahedron Letters, 2001, 42, 4791–4793) disclose the use of preformed complexes of copper dibromide and triphenylphosphine to add aryl halides to secondary aromatic amines.
However, disadvantages of the copper complexes of phosphorus compounds known hitherto are the often low chemoselectivity and the narrow spectrum of reactions in which industrially acceptable conversions and conversion rates can be achieved.
There is, therefore, a need to provide copper complexes of phosphorus compounds which are easy to prepare and afford the desired products in good yields in coupling reactions.